Control device



Oct. 30, 1945.

CONTROL DEVI CE Original Filed April 5, 1959 I-S misas 35 J. D. BoLEsKY Oct. 30, 1945. .1. D. BoLEsKY CONTROL DEVICE original Filed April 5. 1939 5 Sheets-Sheet 2 J. D. BoLEsKY CONTROL DEVICE Oct. 30, 1945.

Patented Oct. 30, 1945 CONTROL DEVICE John D. Bolesky, Attleboro, Mass., assignor to Metals & Controls Corporation, Attleboro, Mass., a corporation of Massachusetts Original application April 5, 1939, Serial No.

266,078. Divided and this 2, 1943, Serial No. 471,140

8 Claims.

This invention relates to control devices, and, with regard to certain more specinc features, to electric snap switches and valves, for example, of both thermally and manually actuated types.

This application is a division of my copending application Serial No. 266,078, filed April 5, 1939, now Patent 2,327,336.

Among the several objects oi the invention may be noted' the provision of a control device of the class described, which is capable of automatic operation to one controlling condition, but which is incapable of automatic operation to a second controlling condition, requiring manual actuation therefor; the provision of a thermally responsive switch of the class described which in case of excess currents being drawn by the motor (or other electrical device) will automatically break the circuit connections to the device; the provision of a thermally responsive Control device of the class described which requires manual resetting in order again to actuate the device; the provision of an electric switch of the class deapplication January y Switches of this type are sometimes called therscribed which is so constructed as to include novel means for preventing the formation of contactdestroying arcs; and the provision of control devices oi the class described which are relatively economical to make, and safe in operation. Other objects will be in part obvious and in part pointed out hereinafter.-

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is a top plan view of a form of switch embodying the present invention;

Fig. 2 is a vertical cross section taken substantially along line li-l 5 of Fig. 1;

Figures 3. 4 and 5 are cross sections taken substantially along lines IB-IB, ll-ll and il-l 8, respectively, oi Fig. 2;

Fig. 6 is a view similar to Fig. 4, illustrating an alternative operating position of the Fig. 1 switch;

Fig. 'l is a vertical cross section taken substantially along line II-N of Fig. 6;

Fig. 8 is a cross section similar to Fig. 6. illustrating another switch embodiment of the present invention; and

Fig. 9 is a cross section similar to Fig. 8, show..

ing the switch thereof in an alternative position. 56.

mal cutouts and more Vparticularly when applied to electric motors, motor overload protective devices. While the switch embodiments of the present invention are applicable to other electrical devices than motors, the invention will be explained and illustrated in an' embodiment as applied to motors.

Figures 1 through 'I show a practical switch embodiment of the invention following the general principles set forth in my Patent No. 2,327,- 336, referred to above. The embodiment of Figures l through '7 has been particularly designed for use as a thermal cutout, or motor overload protective device. This switch has the very practical feature that it automatically breaks circuit connections when the current value exceeds a predetermined limit, or when the ambient temperature exceeds a predetermind limit. 'I'his switch will not re-set itself automatically; that is to say, once circuit connections have been broken, manual actuation is needed in order to reestablish such circuit connections. This is a valuable protective feature in connection with motor overload protection. The switch is so constructed, however, that it may be manually disconnected or connected at any time; and it is accordingly useful as a starting and stopping switch for the motor.

Referring to Figuresl through '7, numeral 30 indicates a base for the switch of cup-like construction, comprising a bottom portion 3| and.

an upstanding, generally cylindrical wall 32. Pro- Jecting out of the top of the cup-shaped base 30 is agenerally cylindrical control knob 33. the particular construction of which will be given in greater detail hereinafter. Both the base 30 and the knob 33 are preferably made of an electrical insulating material, such as molded Bakelite, porcelain, etc. Base 30 is preferably provided with external mounting ears 29.

Mounted centrally in the bottom 3l of the base 30 is a threaded post 34, which has a polygonal the bottom 3 I.

head 35 for adjusting purposes. A lock nut 38 secures the relative adjustment of the post 34 in On the other side of the bottom 3|, the post 34 is extended into knob 33 as an unthreaded cylindrical portion 31 of reduced diameter.

Extending through the bottom ai of the hasey 33 are three electrical terminal pieces 33, 33 and 40, the angular disposition of which about the post 34 is indicated in Fig. 5. Terminal piecesl 38 and 33, it will be seen, are diametrically oppoopposite in direction for each projection of the pair on either side of each ear 58.

fI'he disc 54,-it will be understood, rotates freely in the groove of collar 53, relativeto the post 34. Numeral 60 indicates a coil spring, of general type of a watch spring, the inner end 8| of which is polygonally formed in order to embrace the site each other. The angular position of termlnal piece 40 is relatively immaterial.

The terminal pieces 38, 33 and 40 comprise sheet metal stampings which are force-fitted into the bottom 3| of base 30, affording internal contact faces 4|, 42 and 43, respectively, and ex- Iternal loops 44, 45 and 46, respectively, to which external connections may be made as by soldering. The particular construction of the terminal pieces 33, 33 and 40 is immaterial to the present invention, and hence need not be described at length herein.

Internally of the cup-shaped base 30, the surfalce of bottom 3| is provided with a substantially annular groove 41, which extends approximately concentrically aboutxthe post 34 from terminal piece 39 to terminal piece 40. In the groove 41 is positioned a coiled electrical resistance heater trically connected to terminal piece 39, while the other end is electrically connected to terminal piece 40.

The internal wall of the cylindrical portion 32 83 of the base 30 is provided with diametrically opposite bayonet-type notches 43. extending through, say, about 60 of arc. The notches 43 have, at one diametrically opposite end of each,

periphery of polygonal collar 55. The outer-end 62 of spring 80 is turned into substantially the plane of disc 54, and at, its extremity is hooked into a hole 53 in the disc 54 provided for that purpose. Coil spring |50 is normally in tension, and, reacting centrally on the polygonal collar 55 (which, it will be recalled, is relatively nonrotatable with respect to the post 31), it tends at all times to rotate the disc 54, relative to the post 31, in a counterclockwise manner, considered from the viewpoint represented by Fig. 4. Ad- Justment of the amount of tension in the spring may be made by slipping its polygonal inner end 5| around the polygonal collar 55. In order to do this, the inner end 8| is momentarily pried 55 in a relatively non-movable manner.

Surmounting the polygonal collar 55 on the reduced diameter portion 31 of post 34 is a rela- -tively long sleeve 84, the outer end of which is Wire one end of the heater wire 48 is e1ec 30 outwardly flanged as indicated at numeral 65.

Preferably the sleeve 34 is a forced-rit on the post portion 31, so that it does not rotate relative thereto. Beyond the flange 85, reduced diameter portion 31 is preferably upset and headed over, as indicated at numeral 88.

The inner face of knob 33 is provided with a circular depression 61 of sufllcient depth substantially to enclose the coil spring 30. Extending inwardly from the center of the depression 61 relatively deeper portions 50, extending throughlg is a cylindrical hole es' into the emergent end is a peripherally grooved collar 53, into the groove `of which relatively vloosely fits the internal periphery of a perforated thermostatic metal disc 54 of the samel general type as the disc 23 shown in Fig. 10 of my said Patent No. 2,327,336. The disc 54 is held in position in the groove 53 by a, polygonal, preferably hexagonal collar or nut 55, which clamps down on the collar 53. The collar 55 is force-fitted to the reduced diameter portion 31 of post 3'4, so that it cannot. rotate relative thereto. On the surface of disc 54 facing the bottom 3| are mounted, as by welding, in diametrically opposite positions. a pair of conta-:t buttons 56 and 51, which are positioned at suitable radial distances to engage contact plates 4| and 42 when the disc 54 is concave to the right,

' as illustrated in Figures 2 and 4.

`rically opposite projections 10. Each projection 10 includes, in its under surface and at its outer edge, a notch 1| of sufcient width freely to receive the upstanding projection 58 on the periphery of thermostatic disc 54. The notches 1| are of sumcient depth to accommodate said projections 58 regardless of the direction of concavity of the disc 54.

The projections 10 extend radially outwardly sufficiently far so that they fit only into the bayonet-type notches 43 in the base member 30. By abutting the ends of said bayonet notches 43, the said projections 10 limit the rotative movement of the knob 33 in the base 30.

As shown in Fig. l, the outer face or end of the knob 33 is preferably provided with a position-indicating means, such as .the arrow 33a.

Despite its more complex form, the embodiment of Figures 1 through 7 operates in substantially the same manner as'the embodiment shown in Fig. l0 of my said Patent No. 2,327,336. That is to say, when the thermostatic disc 54 is below a certain temperature, it is concave to the right, in Fig. 2, and it provides pressure between the contacts 55 and 4|, and 51 and 42, respectively,

sufliciently great that the interfacial friction l however, the temperature of the disc 54 increases sumciently in amount, said disc snaps or moves to a position of opposite concavity. i. e., concave to the left in Fig. 2, and in so doing it lifts the contacts 58 and 51 from the contacts 4| and 42. There is then no frictional deterrent to the rotative influence of the spring 80, and consequently the thermostatic disc 54 rotates on the post 31 in a counterclockwise'manner, to the position shown in Fig. 6. When the disc 54 rotates. it carries with it the knob 53, by engagement vof the upstanding projections 58 with the notches 1|. The projections 59 do not interfere with this rotative movement, because when the disc 54 is concave to the left in Fig. 2, said projections 53 are raised above the level of the ledges 52 bottoming the notch portions 5| in base 30.

Assuming now that the disc 54 cools while in its Fig. 6 position, it will snap back to its original position of concavity, i. e., concave to the right in Fig. 2. However, under normal conditions there is no automatic tendency for the disc to rotate back to its Fig. 4 position, so it does not do so, but remains in its Fig. 6 angular position. The projections 59 thus come to rest upon the ledges 52, as shown in Fig. 7. The movable contacts 56 and 51 are now held out of engagement with the fixed contacts 4| and 42 both by reason of the angular displacement of disc 54 and base 30, and by reason of the fact that the engagement of projections 59 with ledges 52 mechanically prevents the disc 54 from overcentering all of the way to its position of right-hand concavity.

After .the disc 54 has thus assumed the Fig. 7 position, it is necessary manually to rotate the knob 33 in a clockwise manner to reestablish circuit connections. By such rotation, the disc 54 is rotated in a clockwise manner through the engagement of projections 58 with notches 1|, and as the projections 59 pass ofi the ledges 52, said projections sink into the deeper notch portions 50, and bring the relatively movable contacts 56 and 51 back into juxtaposition with the relatively iixed contacts 4| and 42.

The positioning of the projections 59 in the deeper notch portions 50 provides anadditional securing means against counterclockwise rotation of the disc 54 under the influence of the coil spring 53, unless said disc 54 is snapped over to its position of leftward concavity.

It will thus be seen that the switch as described is fully capable of automatic circuit-breaking 33, and with it the disc 54, in a counterclockwise manner from the Fig. 4 to the Fig. 6 position. The sloping faces of these projections 59, ride up on the ledges 52 under such manual actuation of the knob 33. It is thus seen that the switch is capable of manual disconnecting operation as well as automatic disconnecting operation. It may accordingly be used as a simple on and oi! switch for an electric motor, for example, with the additional feature of automatic overload protection in its automatic disconnecting capabilities.

By adjusting the threaded portion of post 34 in base 30 an adjustment ofthe operating, or snapping temperature of disc 54 is brought about. The reasons for such action are described at length elsewhere, and need not be repeated herein. Lock nut 33 secures such adjustment once it is made.

Figs. 8 and 9 illustrate an embodiment oi' the invention that operates somewhat differently than the previous embodiments. In this Fig. 8 embodiment it is impossible manually to turn oil? the switch once it is turned on (such turning off being solely automatic), while it is impossible yautomatically to turn on the switch once it has been turned oir (such turning 0n being accomplished solely manually). In prior embodiments the switch can be turned on or ofi, manually, at any time. Switches of the present type are of use in connection with certain types of circuitontrols.

Referring to Figures 8 and 9, it will be seen that the peripherally relatively short notches 1| in the projections 19 on knob 33 are replaced by notches 8| that extend a relatively much longer peripheral distance around the under face of knob 33. In fact, the angular extent of the notches 8| is preferably only slightly less than the angular extent of the bayonet-like notches 49 in spaceiS. By this simple expedient the desired action of the switch is brought about. It will clearly be seen that, with the Fig. S embodiment, and the switch in circuit making position, if the knob 33 is rotated in a counterclock- Wise manner (the same movement that in the Fig. 1 embodiment manually disconnected the switch), the disc 54 will not change in angular position, because the projections 58 willslide freely in the elongated notches 8i until the projections 10 on knob 33 abut the ends of bayonet-like notches 49.

However, when said switch has assumed its automatically disconnected position, and the disc is rotated t0 the full extent in a counterclockwise position, as illustrated in Fig. 9, it may be manually brought back to connecting position in the manner heretofore described, because in this event the projections 58 are engaged by operative ends of the notches 8|.

The embodiment of Fig. 8, therefore, is capable solely of automatic disconnecting operation, and capable solely of manual connecting operation.

In view of the above, it will be seen that the several objects 0f the invention are' achieved and Vother advantageous results attained.

As many changes could be made in carrying out the above constructions Without departing from the scope of the invention, it is intended that all matter contained in the above description 0r shown in the accompanying drawings shall be interpreted as illustrative and not in`a limiting sense.

I claim:

1. A control device comprising a base, a resilient plate mounted substantially parallel to said base and rotatable with respect thereto between two limiting angular positions on an axis perpendicular to the base, at least one projecting member carried by said plate and forced by the resilience thereof against said base, means for manually rotating said plate relative to said base, means limiting the movement of said last-named means to determine the said limiting positions, control-enacting elements determined as to condition by the relative angular positioning of said plate on said base, andmeans interconnecting said `plate and said manually operable means such that said manually operable means is effective to move said plate from one limiting position to the other limiting posiiton, but is ineffective to move said plate in the reverse direction.

2. A control device comprising a base, a resilient thermostatic plate mounted substantially parallel to said base and rotatable with respect thereto between two limiting angular positions on an axisperpendicular to the base, at least one projecting member carried by said plate and forced by the resilience thereof against said base. means for manually rotating said plate relative to said base, means limiting the movement oi said last-named means to determine the said limiting positions, control-eilecting elements determined as to condition by the relative angular positioning o! said plate on said base, and means interconnecting said p1ate"`and said manually operable means such that said manually operable means is eiiective to move said plate from one limiting position to thel other limitingposition, but is ineffective to move said plate in the reverse direction.

3. A control device comprising a base, a resilient thermostatic disc mounted substantially parallel to said base and thereto between two limiting angular positions on an axis perpendicular to the base, at least one projecting member carried by said disc and forced by the resilience thereof against said base, means for manually rotating said disc 'relative to said base, means limiting the movement of said last-named means to determine the said limiting positions, control-eilecting elements determined as to condition by the relative angular positioning of said disc on said base. and means interconnecting said disc and said manually operable means such that said manually operable means is effective to move said disc from one limiting position to the other limiting position, but is ineiective to move said disc in the reverse direction.

4. A control device comprising a base, a resilient thermostatic disc mounted substantially parallel to said base and rotatable with respect thereto between two limiting angular positions on an axis perpendicular to the base,y two projecting members carried by said disc and forced by the resilience thereof against said base, means for manually rotating said disc relative to said base, means limiting the movement of said lastnamed means to determine the said limiting positions, control-eiecting elements determined as to condition by the relative angular positioning of said disc on said base, and means interconnecting said disc and said .manually operable means such that said manually operable means is effective to move said disc from one limiting position to the other limiting position, but is ineiective to move said disc inthe reverse direction.

rotatable with respect nessus 5. A control device comprising a base, a resilient thermostatlc disc mounted substantially parallel to said base and rotatable with respect thereto between two limiting angular positions on. an axis perpendicular to the base, two`pro Jecting contacts carried by said disc and forced by the resiliencethereoi against said base, means for manually rotating said disc relative to said base, means limiting the movement of said lastnamed means to determine the said limiting positions, stationary contacts on said base positioned to engage said movable contact when said disc is in one limiting position, and means interconnecting said disc and said manually operable means such that said manually operable means is eiective to move said disc from one limiting position to the other limiting position, but is ineidective to move said disc in the reverse direct on.

6. A control device comprising a base, a resilient plate mounted onsaid base and rotatable with respect thereto, at least one projecting member carried by said plate and forced by the resilience thereof into frlctional engagement with said base, means for rotating said plate relative to said base from one limiting vposition to another limiting position but ineffective to move said plate in the reverse direction and controlefiectlng elements determined as t0 condition by the relative rotative positioning of said plate on said-base.

7. A control device comprising two relatively rotary members, at least one contact carried on one of the members, a resilient plate mounted on the other member, a contact on said plate adapted to engage and disengage the first-named contact upon relative rotary movement, means connecting the relatively rotary parts for biasing the plate in a direction to press the contacts when they are closed and to tension said plate, and

means interconnecting said plate and said other member so that said rotary movements are effective to move said plate from one limiting position to another limiting position but are ineffective to move said plate in the reverse direction.

8. A control device comprising a base, a resilient plate mounted on said base and 'rotatable with respect thereto, said plate 4having formed.

therein a projecting part, and said projecting part being forced by the resilience of said plate into frictional engagement with said base, means for rotating said plate relative to said base from one limiting position to another limiting position but ineffective to move said plate in the reverse direction, and control effecting elements determined as to condition by the relative rotative positioning of said plate on said base.

JOHN D. BOLESKY. 

